The most trusted source for amateur radio headphones, headsets and microphones is Heil Sound.
Heil Amateur Radio - Ham Radio Receivers - Mics - Headsets - Accessories
Most trusted by a few hams but not necessarily by people who actually know audio. You can also use stereo headphones with an adapter cable to combine two headphone channels into one. That will give you more options and you might already have some stereo phones that are perfect and just need a mono adapter.
I have four of their products and I'm very pleased with them. Possibly the worst headphones I have are a set of Beats Pro phones. The kids love them and I will say they have great audio, but the Pro model is heavy, the cushions are hard and the ear opening not large enough. For something that costs almost $400 retail, they are horribly uncomfortable. I'm glad I didn't pay for them.